The present invention relates to a positive stopping device for a tape measure. In conventional tape measures, a frictional engagement or pressing means has been provided at a side of the tape measure body and stopping of the tape measure has been carried out by pressing the stopping means into frictional engagement with the marked face of the measure or tape. After repeated uses, there is a possibility that the measuring indicia can be wiped from the face of the tape and even if this does not occur, the stopping means is not positive in the sense that there is only a frictional engagement which makes movement of the tape measure somewhat more difficult but does not provide any kind of actual positive locking mechanism for the tape measure.
There are a variety of patents which have issued some recently and some not so recently which show mechanism for positively stopping a tape measure but all of these devices fail to provide the type of control necessary for carpentry uses or require expensive mechanisms to modify standard tape measures. For instance, the Kang U.S. Pat. No. 4,856,726 issued Aug. 15, 1989 shows a stopping device for a tape measure wound on a spool or reel but the device is adaptable only to a large tape measure device and requires an expensive interrupt mechanism to be added onto the casing of the tape measure, the entire combination being much too clumsy and much too large to be incorporated into the standard tape measure of the type commonly sold at hardware stores for carrying on a carpenter's belt or useful around the house. Moreover, the tape measure cannot be stopped at small intervals.
U.S. Pat. No. 4,531,688 issued to Gail Jul. 30, 1985, also shows a positive stopping mechanism for a measuring tape. In the Gail device, an entirely new spool has to be designed in order to accommodate what is essentially a clutch device wherein the clutch has to move axially with respect to the drum. This device while perhaps satisfactory, involves the kind of moving parts which can cause difficulty when a tape measure is subjected to kinds of abuse encountered in the field when used by construction carpenters also requires a relatively complex mechanism in comparison to the invention hereinafter disclosed. In addition, the tape measure cannot be stopped at small intervals.
Other patents of general interest include the Buttigieg U.S. Pat. No. 2,071,225 issued Feb. 16, 1937 and the Gasstrom U.S. Pat. No. 2,080,815 issued May 18, 1937, both for measuring tape devices. Neither of these patents show the kind of stopping mechanism which is the subject of the invention, that is a positive locking mechanism which is capable of locking the measuring tape at 1/16 to 1/8 inch intervals and which requires no actual moving parts but relies instead on a simple straight forward device which nevertheless provides the positive interlock needed by carpenters and the like.